Sebaceous Cysts

Lumps, Bumps and Sebaceous Cysts

A very large sebaceous cyst being removed in its entirety from the scalp under local anaesthetic. Only complete removal of the cyst will ensure that it does not return. Cysts often look like a small pearl, but can grow to the size of a golf ball. Commonly occur on the head, neck and back regions.

Sebaceous cysts often appear as a mobile, round, firm lump just under the skin surface. Essentially starting as a blocked oil gland within the skin's dermis layer, a sebaceous cyst begins as the size of a pin head, and slowly starts to grow over many years to become the size of a small pea or pearl. In some cases it can grow to the size of a golf ball!

Unlike a pimple, sebaceous cysts are sterile inside, containing waxy oils and are not usually bacterially infected. However, if bacteria do get access into a sebaceous cyst, they can certainly become a power house of infection, causing a lot of swelling, tension, redness and discomfort, requiring a hefty dose of antibiotics and usually necessitating surgical lancing to relieve pressure and pain and speed up healing (at this point they are more like a very large nasty boil). Treating like this however, will not "cure" the sebaceous cyst, only rid the infection. The cyst will simply regenerate and continue to grow again (see below for correct and permanent removal of a sebaceous cyst).

Multiple sebaceous cysts removed from a scalp under local anaesthetic. All have been removed as complete sacks and will not recur.

Sebaceous cysts are common, and usually occur in areas such as the scalp, face, earlobes, neck, shoulders and back, but can occur anywhere there is skin. There doesn't seem to be any gender preference, and I have seen them in children (rare) and in adults. The longer a sebaceous cyst exists (and they tend to be slow growing over many years), the larger it tends to become, to the point where it simply starts to become visibly obvious or of a size that becomes bothersome. A small skin lump that rapidly increases in size and discomfort, is most likely to be an infected sebaceous cyst and medical advice should be sort.

Often confused with sebaceous cysts are Lipomas. These are non-cancerous fatty lumps often just under the skin, are also relatively common, can be similar in size (but can often grow much larger), and generally occur in areas where there is some bulk or fat such as the trunk/torso, upper arms and legs, but I have also seen them on the side of the face and neck (click link Lipomas for more information). There are many other causes of lumps, some of which are not so benign. Luckily these tend to be rare, but for any lump, I suggest you obtain a medical opinion.

Removal of Sebaceous Cysts
Removal of a sebaceous cyst is a minor surgical procedure performed under local anaesthetic. The most important thing in this procedure is to remove the cyst in it's complete entirety. Failing to do so will be guaranteed to result in the eventual return of the cyst - months to years later. This is because the active growing part of the cyst is only the outside shell or sack, with the contents and hence size of the sack, merely being made up of dead waxy material. If the cystic sack is simply lanced or popped, or surgical removal is done poorly or in a piecemeal fashion leaving even a small fraction behind, the sebaceous cyst will simply once again regrow from these small beginnings.

Removed correctly, the cyst should ideally come out as a complete sack, looking somewhat like a creamy coloured pearl. This is what usually happens, but I have occasionally come across very stubborn or multi-lobed cysts (tethered, bubbly, irregular sack). These stubborn difficult types of cysts are usually the product of previous infection and inflammation (or previous incomplete removal). This is also a good reason why playing or fiddling with a sebaceous cyst is not a good idea (some people just cant help touching and squeezing them over the years), as irritating a cyst over many years also tends to make them more tethered to the surrounding tissue. In cases of difficult removal, I have found my erbium laser to be an invaluable tool to help remove any remaining pieces of cyst remaining down in the depths of an inaccessible small wound.

The key to removing a sebaceous cyst with minimal or no residual scar is four fold:
1) making the smallest single linear incision in the skin over the cyst, as is possible (unlike the surgical removal of something like a mole or skin cancer where an elipse of skin includes cutting and removing skin around the mole, for a cyst removal no such skin needs to be removed).
Too long a cut, and the cyst may be easier to remove, but the long term scar is less desirable. The problem with an incision that is that too small, is it becomes a bit like trying to remove a watermelon through the eye of a needle! However, with a careful and skillful approach, the wound can be small and the cyst eased out in it's entirety.
2) appropriate consideration to the placement and orientation of the surgical cut, will help reduce local stress on the healing wound.
3) impeccable wound closure and suturing. Commonly used individual type surface stitches, give poor long term scar results, often looking like a scar line with halo or "eye-lash" effect either side of it. A hidden "underground" type single suture appropriately placed, will give a much better result.
4) taping the wound line for up to 12 weeks post surgery (not always practical or possible) will help prevent stretching or splaying of the scar

   
   
  

Photos of the removal of a moderately large sebaceous cyst on a back. A single linear incision with no skin removal is performed under local anaesthetic that has an antibleeding agent added to it. Note the complete removal of the intact cyst, which will ensure that it will not grow back in the future. Note the removal of the cyst through a surgical cut that is smaller than the size of the cyst, and the wound closure with a specialised single "underground" stitch. This, along with proper aftercare, will ensure a small and discrete scar which will fade with time to a minimal mark. Unnecessary skin removal or lesser ordinary stitching, involving individual stitches crossing over the wound on the skin surface, will result in stretching apart of the scar and the "eye-lash" effect commonly seen around old scars that have been poorly sutured.

 Small incision exposes cyst mid cheek.

 Cyst removed; this wound is simply glued.
 

 1 year later no scar is visible!